Electrical stimulation in deep brain structures (DBS) has developed into an effective treatment for advanced Parkinson's disease and essential tremor. DBS also is being evaluated as a treatment for other neurological conditions and appears to be useful in the treatment of several types of dystonias and hyperkinetic disorders and for intractable temporal lobe epilepsy. The subthalamic nucleus has become the preferred target for the treatment of advanced Parkinson's Disease and certain other motor disorders by DBS. Numerous studies have demonstrated a topographic organization of the STN of many species, including humans. It is likely that a clinical device that can access this topology will afford greater opportunities and flexibility in the treatment of motor disorders than is possible with the deep brain arrays now in clinical use. The present devices use macroelectrodes, and the electrical stimulation tends to spread quite broadly, and may extend well beyond the boundaries of the STN, which may account for many of the side effects that often accompany deep brain stimulation in the STN. An array of stimulating microelectrodes distributed through the target nucleus would permit precise control of the spatial distribution of the stimulation, allowing for better individualization of DBS therapy and a lower incidence of side effects. However, a novel array for clinical DBS must retain all of the functionality of the devices now in clinical use, as well as providing new capabilities. Our objective is develop the technology for arrays of microelectrodes that are suitable for chronic implantation into the human subthalamic nucleus (STN), the internal segment of the globus pallidus, and perhaps other targets in the deep brain, are able to record chronically from single neuronal units, and can deliver localized microstimulation and "sculpted" stimulation with much better control of the spatial pattern of stimulation than is possible with the arrays now in clinical use, but are fully "backward compatible" with the present clinical arrays. In addition to its clinical applicability, this technology can be used in animal studies aimed at understanding the mechanisms by which deep brain stimulation can ameliorate the symptoms of Parkinson's Disease and other movement disorders. This technology will improve quality of life for persons afflicted with Parkinson's Disease and other movement disorders.